This is in line with reports that found increased frequencies of NKG2D+ CD4+ or CXCR6+ CD4+ T cells at the site of autoimmune inflammation in patients suffering from multiple sclerosis, rheumatoid arthritis, or systemic lupus erythematosus (22, 27, 45, , –48). Here, CXCR6 is linked to rheumatoid arthritis.